scan: enable high precision output

scan now provides float image data to libavcodec for encoding instead of
rounding to 8 bit RGB, allowing for writing in full precision to formats
like portable floatmap.

Output bitdepths will now be higher by default for all formats that
support this; this may still be controlled by explicitly setting the
pixel format with e.g. --ff-opts pixel_format=rgb24

include/ffapi.h

@@ -11,6 +11,7 @@
 #include <libavformat/avformat.h>
 #include <libavutil/pixdesc.h>
 #include <libavutil/parseutils.h>
+#include <libavutil/intreadwrite.h>
 #include <assert.h>
 #include <stdbool.h>
 
@@ -49,7 +50,6 @@ size_t    ffapi_seek_frame (FFContext*, size_t offset, void (*progress)(size_t))
 int       ffapi_write_frame(FFContext*, AVFrame*);
 int       ffapi_close(FFContext*);
 
-// 8 bit only for now
 #define FFA_PEL(frame,comp,x,y) frame->data[comp.plane][y*frame->linesize[comp.plane]+x*comp.step+comp.offset]
 static inline void ffapi_setpel_direct(AVFrame* frame, size_t x, size_t y, AVComponentDescriptor comp, unsigned char val) {
 	assert(comp.depth == 8);
@@ -72,6 +72,17 @@ static inline void ffapi_setpell_direct(AVFrame* frame, size_t x, size_t y, AVCo
 		    default: (ffapi_setpel_direct)(AVFrame,x,y,comp,       val)\
 	)
 
+static inline void ffapi_setpelf(FFContext* ctx, AVFrame* frame, size_t x, size_t y, int c, float val) {
+	AVComponentDescriptor comp = ctx->pixdesc->comp[c];
+	assert(comp.depth == 32 && (ctx->pixdesc->flags & AV_PIX_FMT_FLAG_FLOAT));
+	uint32_t valu = (union { float f; uint32_t u; }){val}.u;
+	uint8_t* data = &FFA_PEL(frame,comp,x,y);
+	if(ctx->pixdesc->flags & AV_PIX_FMT_FLAG_BE)
+		AV_WB32(data,valu);
+	else
+		AV_WL32(data,valu);
+}
+
 #define ffapi_setpel(FFContext,AVFrame,x,y,c,val) ffapi_setpel_direct(AVFrame,x,y,FFContext->pixdesc->comp[c],val)
 #define ffapi_getpel(FFContext,AVFrame,x,y,c) ffapi_getpel_direct(AVFrame,x,y,FFContext->pixdesc->comp[c])
 #define ffapi_setpixel(FFContext,AVFrame,x,y,val)\

scan/scan.c

@@ -251,13 +251,10 @@ int main(int argc, char* argv[]) {
 	}
 	size_t width = MagickGetImageWidth(wand), height = MagickGetImageHeight(wand), channels = 3;
 
-	unsigned char blackpixel[channels];
-	memset(blackpixel,0,channels);
-
 	av_log_set_level(loglevel);
 	FFColorProperties color_props;
 	ffapi_parse_color_props(&color_props,"");
-	color_props.pix_fmt = AV_PIX_FMT_RGB24;
+	color_props.pix_fmt = AV_PIX_FMT_GBRPF32LE;
 	color_props.color_range = AVCOL_RANGE_JPEG;
 	int imagecolorspace = MagickGetImageColorspace(wand);
 	if(imagecolorspace == RGBColorspace)
@@ -375,8 +372,8 @@ int main(int argc, char* argv[]) {
 				if(visualize) {
 					intermediate normalization = spec_normalization_2d(x,y);
 					for(size_t z = 0; z < channels; z++) {
-						intermediate c = (spec ? spec_scale(sp,coeffs[(y*width+x)*channels+z]*normalization) : 1.0)*255;
-						ffapi_setpel(ffctx,frame,x+width,y,z,c);
+						intermediate c = spec ? spec_scale(sp,coeffs[(y*width+x)*channels+z]*normalization) : 1.0;
+						ffapi_setpelf(ffctx,frame,x+width,y,z,c);
 					}
 				}
 			}
@@ -390,7 +387,7 @@ int main(int argc, char* argv[]) {
 					intermediate pel = sum[(y*width+x)*channels+z];
 					if(trc_encode)
 						pel = trc_encode(pel);
-					ffapi_setpel(ffctx, frame, x, y, z, pel*255);
+					ffapi_setpelf(ffctx, frame, x, y, z, pel);
 				}
 	}
 
@@ -410,10 +407,10 @@ int main(int argc, char* argv[]) {
 			if(visualize) {
 				intermediate normalization = spec_normalization_2d(x,y);
 				for(size_t z = 0; z < channels; z++) {
-					intermediate c = (spec ? spec_scale(sp,coeffs[(y*width+x)*channels+z]*normalization) : 1.0)*255;
-					ffapi_setpel(ffctx,frame,x+width,y,z,c);
+					intermediate c = spec ? spec_scale(sp,coeffs[(y*width+x)*channels+z]*normalization) : 1.0;
+					ffapi_setpelf(ffctx,frame,x+width,y,z,c);
 					if(intermediates)
-						ffapi_setpel(ffctx,frame,x+width,y+height,z,c);
+						ffapi_setpelf(ffctx,frame,x+width,y+height,z,c);
 				}
 			}
 		}
@@ -432,7 +429,7 @@ int main(int argc, char* argv[]) {
 					intermediate pel = sum[(y*width+x)*channels+z];
 					if(trc_encode)
 						pel = trc_encode(pel);
-					ffapi_setpel(ffctx, frame, x, y, z, pel*255);
+					ffapi_setpelf(ffctx, frame, x, y, z, pel);
 				}
 
 		if(intermediates) {
@@ -463,7 +460,7 @@ int main(int argc, char* argv[]) {
 						intermediate pel = (((image[(y*width+x)*channels+z]+coeffs[z])-min[z])/(max[z]-min[z]));
 						if(trc_encode)
 							pel = trc_encode(pel);
-						ffapi_setpel(ffctx, frame, x, y+height, z, pel*255);
+						ffapi_setpelf(ffctx, frame, x, y+height, z, pel);
 					}
 		}
 
@@ -474,7 +471,8 @@ int main(int argc, char* argv[]) {
 		// just clear intermediate coords instead of wiping the entire frame
 		if(intermediates && visualize)
 			for(size_t ci = 0; ci < ncoords; ci++)
-				ffapi_setpixel(ffctx, frame, coords[ci][1]+width, coords[ci][0]+height, blackpixel);
+				for(size_t z = 0; z < channels; z++)
+					ffapi_setpelf(ffctx, frame, coords[ci][1]+width, coords[ci][0]+height, z, 0);
 	}
 	if(!quiet)
 		fprintf(stderr,"\n");